The invention relates to an apparatus for automatic application of blood serum, and more particularly to such apparatus for use in a blood serum analyzer of cataphoretic type in which a blood serum applied to a serum bearing film, which is used for producing a specimen, is fractionated into components by a cataphoresis process and then the fractions are subjected to a determination with a densitometer or filter photoelectric colorimeter for the purpose of quantitative analysis of the serum components.
In a cataphoretic serum analyzer, it is necessary that a buffer solution be coated on the serum bearing film before the serum is applied to the film in order to render the film in a condition readily susceptible to the cataphoretic process. Usually, a cellulose acetate film is often used as the serum bearing film. However, the cellulose acetate film has a multitude of fine pores, so that if it is directly immersed into a buffer solution, the bubbles in the pores will be confined therein by the solution, to remain as white spots. When the serum is subsequently applied to the film and electrically energized to effect a cataphoretic process, the presence of the remaining air prevents a cataphoretic movement of the serum components and thus precludes a smooth formation of fractionated patterns. To avoid such difficulty, it has been the practice to immerse the film in the buffer solution by floating a support on the surface of the solution and to submerge it gently thereinto, so as to avoid trapping of the air bubbles. Subsequent to the immersion, the film is removed from the solution and is held sandwiched between a pair of paper filters to absorb an excess amount of the solution before the film is passed to the serum application and the energization steps. Thus, the immersion and the removal of excessive liquid require a considerable length of time and a certain degree of skill with attendant care, which stood in the way of automation of the process steps.
In the automation of the serum application, it will be most favorable that the same applicator be used repeatedly. This requires that the applicator be rinsed and dripped after each serum application. Because of the troublesome operation which must be performed on the serum applicator, efforts towards automation of the application have been unsuccessful, and instead a blood serum has been introduced into a micro pipette to draw a line therewith for the purpose of applying the serum. However, such an application operation requires a high level of skill, and must be carefully performed by a skilled operator. Moreover, an accurate determination is prohibited unless the serum application is achieved in a proper manner.